82 research outputs found
6-loop anomalous dimension of a single impurity operator from AdS/CFT and multiple zeta values
Anomalous dimension of the simplest nontrivial single impurity operator in
the beta=1/2 deformed theory is determined at six loops from the AdS/CFT
correspondence. L\"uscher correction is evaluated at next-to-next-to-leading
order (NNLO) in terms of multiple zeta values. The result can be simplified
into the products of simple zeta functions and the same form of the correction
is expected for the Konishi operator at six loops, too.Comment: 14 pages, references added, numeric coefficient in (5) corrected,
which changes the numerical result, but not its structur
Discrete physical states and correction terms in the Supersymmetric c=1 Model of String Theory
In this work, we explore the example of supersymmetric c=1 model which is one
of the simplest models of superstrings, with an elegant and transparent
spectrum of physical states. We show how the presence of the ghost cohomologies
enlarges the spectrum of states and leads to new intriguing symmetries of the
theory and possibly leads to nontrivial relations of two-dimensional
supergravity with physical theories in higher dimensions. We develop a general
prescription for constructing the BRST-invariant and nontrivial vertex
operators and we explicitly compute correction terms that restore BRST
invariance of their corresponding currents.Comment: 15 pages. arXiv admin note: substantial text overlap with
arXiv:hep-th/0602209, arXiv:hep-th/0701044 by other author
The Dynamics of COVID-19 spread: Evidence from Lebanon
We explore the spread of the Coronavirus disease 2019 (COVID-19) in Lebanon
by adopting two different approaches: the STEIR model, which is a modified SEIR
model accounting for the effect of travel, and a repeated iterations model. We
fit available daily data since the first diagnosed case until the end of June
2020 and we forecast possible scenarios of contagion associated with different
levels of social distancing measures and travel inflows. We determine the
initial reproductive transmission rate in Lebanon and all subsequent dynamics.
In the repeated iterations (RI) model we iterate the available data of
currently infected people to forecast future infections under several possible
scenarios of contagion. In both models, our results suggest that tougher
mitigation measures would slow down the spread of the disease. On the other
hand, the current relaxation of measures and partial resumption of
international flights, as the STEIR reveals, would trigger a second outbreak of
infections, with severity depending on the extent of relaxation. We recommend
strong institutional and public commitment to mitigation measures to avoid
uncontrolled spread.Comment: The final preprint of the published paper that covers data from
February 21 until July 1, 2020 and incorporates travel effects. 15 pages, 7
figure
Fruitless (fru) and the Neural System of Rejection Behaviours in Female Drosophila melanogaster
Among sexually reproducing organisms, species are separated by their inability to reproduce with each other and form viable, fertile offspring. One type of reproductive barrier is behavioural, whereby mating is not initiated between two species. In the model organism Drosophila melanogaster, a gene called fruitless regulates heterospecific courtship and rejection behaviours, however, its neural mechanisms of action remain unknown in females. In this work, I identified which fruitless splice variants are expressed in adult males and females, and created the plasmid vectors necessary to implement a genetic system for the purposes of identifying, silencing, and hyperactivating neuronal subsets that express distinct splice-variants of fruitless. These plasmid vectors can be used in the future to induce expression of exogenous genes of interest for further experimentation in D. melanogaster
Finite-Volume Spectra of the Lee-Yang Model
We consider the non-unitary Lee-Yang minimal model in three
different finite geometries: (i) on the interval with integrable boundary
conditions labelled by the Kac labels , (ii) on the circle
with periodic boundary conditions and (iii) on the periodic circle including an
integrable purely transmitting defect. We apply integrable
perturbations on the boundary and on the defect and describe the flow of the
spectrum. Adding a integrable perturbation to move off-criticality
in the bulk, we determine the finite size spectrum of the massive scattering
theory in the three geometries via Thermodynamic Bethe Ansatz (TBA) equations.
We derive these integral equations for all excitations by solving, in the
continuum scaling limit, the TBA functional equations satisfied by the transfer
matrices of the associated RSOS lattice model of Forrester and Baxter
in Regime III. The excitations are classified in terms of systems. The
excited state TBA equations agree with the previously conjectured equations in
the boundary and periodic cases. In the defect case, new TBA equations confirm
previously conjectured transmission factors.Comment: LateX, 42 pages with 22 eps figure
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